Antipsychotic Drugs

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*Chlorpromazine Hydrochloride*

#Formulations :
Chlorpromazine tablet
Chlorpromazine injection
Chlorpromazine elixir
Chlorpromazine suppositories


#Brand_Names : Largactil, Megatil, Sunprazin, Chlorozine, Clozine, Talentil - T, Talentil Forte


#Pharmacological_Action : It produces its antipsychotic effect by the post synaptic blockade at the D2 receptors in the mesolimbic pathway. However, the blocking of D2 receptors in the nigrostriatal pathway is responsible for its extrapyramidal side effects. The antiemetic effect of chlorpromazine stems from the combined blockade of Histamine H1, dopamine D2, and muscarinic M1 receptors in the vomiting centre.
It is extensively metabolised by the liver. It also undergoes metabolism in the kidney and GI tract. It is excreted in the urine, bile, and feces. It has a half life of between 23 and 37 hours for the parent drug, and its active metabolite has a half life of 10 to 40 hours.


#Side_Effects : dry mouth, dizziness, urine retention, blurred vision, constipation


#Therapeutic_Uses : used as antipsychotic drugs.

*Haloperidol*

#Formulations : Tablet, Injection, Oral Liquid, Drops

#Brand_Names : Serenace, Senorm, Halopidol


#Pharmacological_Action : It has high potency and pharmacological profile resembling that of piperazine substitute phenothiazines. It is not selective for D2 receptors. It is metabolised by CYP3A4 and 2D6  both. Elimination t½ averages 24 hours.


#Dose : 1- 10 mg BD


#Therapeutic_Uses : used as antipsychotic Drugs.

*Sulpiride*


#Formulations : Tablet

#Brand_Names : Sulpitac, Skizotus, Amazeo.


#Pharmacological_Action : It produces few extrapyramidal side effects and improves many negative symptoms of schizophrenia as well. It retains high affinity to D2 & D2 receptors and low affinity towards 5- HT2 receptors. Risk of weight gain and metabolic complications is low, but Q-T prolongation has been observed, especially in predisposed elderly patients. It is absorbed orally and mainly excreted unchanged in urine with a t½ of 12 hours.


#Dose : 50- 300 mg / day in 2 doses for schizophrenia with predominant negative symptoms. Also for acute psychosis 200- 400 mg BD.


#Therapeutic_Uses : used as antipsychotic drugs.

*Olanzapine*

#Formulations : Tablet, Injection

#Brand_Names : Oleanz, Olace, Ozap.


#Pharmacological_Action : It works by blocking D2, 5- HT2, alpha 1, alpha 2 , muscarinic and H1 receptors. It is a potent muscarinic produces dry mouth and constipation. Weaker D2 blockade results in few extrapyramidal side effects and little rise in prolactin levels, but is more epileptogenic than high potency phenothiazines. Agranulocytes has not been reported. It is metabolised by CYP1A2 and glucuronyl transferase. The t½ is 24 - 30hours.


#Dose : 5- 20 mg / day.


#Therapeutic_Uses : used as antipsychotic drugs

*Quetiapine*

#Formulations : Tablet


#Brand_Names : Qutipin, Seroquin, Socalm.

#Pharmacological_Action : It blocks 5- HT¹A , 5- HT2, D2, A1,A2, and H1 receptors in the brain, but D2 blocking activity is low: extrapyramidal and hyperprolactinaemic side effects are minimal. However, it is quite sedating, and major portion of daily dose is given at night. It is metabolised by CYP3A4; can interact with macrolides, antifungals, anticonvulsants.



#Dose : Initially 50 mg/day, increase gradually as needed upto 400 mg/day.



#Therapeutic_Uses : used as antipsychotic drugs.